SIREGAR, A. N. Transformational leadership of the principal in improving the professional competence of teachers at SMA Negeri 1 Sosopan, Padang Lawas Regency. Holistic Science, [S. l.], v. 5, n. 3, p. 364–370, 2025. DOI: 10.56495/hs.v5i3.1535. Disponível em: https://jurnal.larisma.or.id/index.php/HS/article/view/1535. Acesso em: 25 feb. 2026.